JPS62171506A - Piston seal for both pressures - Google Patents

Abstract

PURPOSE:To improve low friction characteristic and durability of the piston seal in the caption by connecting a sliding side part constructed by a protrusion and a sliding face to a fixed side part constructed by an inner periphery protrusion and a recessed part through a thin wall part. CONSTITUTION:A sliding side part 2 consisting of a protrusion 12 by a circular arc 12 and a sliding face formed by a tapered face 14 which connects the circular arc 11 to an outer periphery side end part is connected to a fixed side part 3 consisting of an inner periphery protrusion 15 and a recessed part 16 through a thin wall part 9. By this construction, when large friction force is generated by fluid pressure and movement of a piston rod, the sliding side part 2 is deformed by twisting around the thin wall part 9, then low friction characteristic and durability of a piston seal can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention provides a dual-pressure piston seal that is attached mainly to the piston portion of a fluid pressure cylinder and that has excellent low friction characteristics and seals fluid pressure from both directions with one piece. Regarding.

As a piston seal for both pressures of a conventional technology fluid pressure cylinder, O-
There are seals such as rings and X-rings, and improved versions of these seals are also available. However, in these conventional dual-pressure piston seals, the compression type seals such as O-rings are easily damaged by twisting, and in order to reduce the frictional force, the crushing allowance must be reduced and durability must be sacrificed. . The seal, which has an X-ring shape with each protrusion in the shape of a lip, has a large frictional force because the two outer lips contact the cylinder tube, and the thickness of the lip cannot be made too thin due to the relationship with strength. However, it was difficult to ensure durability as a low-friction seal.

C1 Problems that the invention sought to solve The present invention aims to improve the low friction characteristics and durability of the above-mentioned piston seal for the same pressure, and achieves operational responsiveness at low pressures and smooth operation at low speeds. It is an object of the present invention to provide a piston seal for the same pressure with low friction and characteristics.

20 Means for Solving the Problems The present invention solves the above problems by providing a piston seal for equal pressure with a protruding part formed by an arc at the center of the sliding surface,
An opening side part in contact with 1 on the cylinder tube surface consisting of both tapered surfaces connecting the outer circumferential side ends of both side surfaces that are in contact with the circular arc and on the inner circumferential side from the tip of the circular arc, and an inner peripheral protrusion on both side surfaces of the inner circumferential surface. A fixed side part with a recess provided between both protruding parts, a tip part with one small arc provided on both sides, and an I
The vertically symmetrical cross-sectional shape is connected by a thin wall portion sandwiched by a trough formed by the slope of the fixed side portion of the M moving portion.

As a result, in the same-pressure piston seal of the present invention, when a large frictional force is generated due to fluid pressure or movement of the piston rod, the sliding side part easily twists and deforms around the thin wall part sandwiched between the Okaya parts. This is an attempt to solve the above problem by causing the problem to occur.

E. Example One embodiment of the same-pressure piston seal according to the present invention is shown in FIG. 1, and another embodiment is shown in FIG.

The same-pressure piston seal 1 shown in FIG. 1 has a protrusion 12 formed by a circular arc 11 at the center of the outer sliding surface, and a tapered surface 14 that contacts the circular arc 11 and connects the outer circumferential ends 13 of both side surfaces 4.
A sliding side portion 2 having a sliding surface 5 consisting of a sliding surface 5 and an inner peripheral surface 6
A fixed side part 3 consisting of an inner circumferential protrusion 15 provided on both side surfaces 7 and a recess 16 between both inner circumferential protrusions, and a tip part 18 formed by one small circular arc provided on both upper and lower sides. and are connected by a thin wall portion 9 sandwiched between a valley portion 8 consisting of a slope 19 on the sliding side and a slope 20 on the fixed side, and have a vertically symmetrical cross-sectional shape.

A plurality of grooves 21 or protrusions (not shown) 22 may be provided on both side surfaces 4 of the sliding side portion 2 in the radial direction.

Another embodiment, shown in FIG. The sliding surface between the side end portion 13 is a curved surface 25 centered on the thin wall portion 9,
18 The movable side part 2 is configured lower than the fixed side part 3, and the fixed side part 3 is lower than the fixed side part 3.
A piston seal for equal pressure is not shown in which a second trough 26 is provided in the inner peripheral surface and a thin lip 27 is formed in the portion that contacts the groove bottom surface 34 on the inner circumferential surface.

Effects and Effects In the piston seal 1 for equal pressure according to the present invention, the contact state between the sliding surface 5 of the piston seal and the cylinder tube surface 31 changes due to a long period of rest, etc., and the frictional force at the time of starting becomes large. Even in this case, the sliding side portion 2 twists around the thin wall portion 9 sandwiched between the valleys due to the frictional force with the cylinder tube surface, and the sliding surface 5 of the sliding side portion 2 and the cylinder tube surface 31 are twisted. They come into contact with each other through new surfaces, making it possible to reduce frictional force.

As this twisting occurs in the 18 moving side portion 2, the frictional force between the sliding surface and the cylinder tube surface is converted into rolling friction due to torsion instead of sliding friction due to sliding as in the case of a normal seal. Frictional forces, especially during starting, are significantly reduced.

The greater the frictional force, the greater the twisting of the moving side portion 2, and the twisting corresponds to the frictional force.

This behavior of the sliding side is caused by changes in the frictional force during normal opening movement (estimated to be due to changes in the dimensions of the cylinder tube, local scratches, changes in the lubrication state, etc.). Since it is absorbed by the torsion of the parts, there is little change in the frictional force during sliding, which is very effective in lowering the critical speed at which the so-called stick-slip phenomenon occurs in one motion at low speed.

Furthermore, by forming the protruding portion 12 of the sliding surface with a plurality of small circular arcs 23 and recesses 24, the lubricant is retained in the recesses, which prevents insufficient lubrication and improves the durability of the seal. .

By configuring the sliding surface between the circular arc of the protruding portion of the sliding surface and the outer circumferential end of both side surfaces as a curved surface 25 centered on the thin wall portion 9, the center of torsion of one surrounding side portion can be Since it is located near the center of the circular arc, twisting of one occupied side portion can be performed without difficulty.

1 The height of the movable side part 2 is made lower than the fixed side part 3, and the gap between the side face 4 of the sliding side part and the side face 35 of the mounting groove is set large. By setting the thickness of the connecting thin wall portion 9 to be thin, twisting of the side portion of the first side portion can easily occur, and characteristics at low pressure and low speed can be improved.

Generally speaking, the same-pressure piston seal according to the present invention is constructed symmetrically in the upper and lower directions, that is, in both pressure directions, so there is no difference in performance depending on the direction of pressure or movement.

The characteristics of the same pressure piston seal according to the present invention are as follows! The size of the circular arc 11 on the moving side, the angle of the tapered surface 14 with the cylinder tube surface 31, the thickness of the thin wall portion 9, the depth of the recess 16 on the fixed side, the hardness of the synthetic rubber and elastomer material, By setting these, it is possible to obtain a seal that corresponds to the fluid pressure and frictional force used.

lThe arc of the moving side is small, the angle of the tapered surface is large, the thin part is thin, the recess of the fixed side is deep, and a second valley is provided on the fixed side, making it relatively soft. If the material is selected, it is possible to obtain a piston seal for the same pressure with excellent low friction characteristics.

From the results of the test according to the example, it is preferable that the angle of the tapered surface 14 with the cylinder tube surface is 10 to 45 degrees, and that the opening angle of the troughs 8 on both sides is equal to the angle of the part of the taper, and that the sliding If a large frictional force or pressure is applied to the side part and excessive twisting occurs, the slope 19 of the sliding side part and the slope 20 of the fixed side part will come into contact, restricting the twisting of the sliding side part 2, and damage the seal. prevent.

When the thickness of the thin portion 9 is made smaller than the diameter of the circular arc 11 of the sliding surface, low friction and satisfactory durability have been obtained.

The same-pressure piston seal of the present invention is attached to the piston portion of a fluid pressure cylinder and exerts its function best as a piston seal on which pressure acts from both directions. By reversing it, it can be used not only as a seal for the piston part but also for the rod part.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams showing one side of an embodiment of the present invention in cross section. FIG. 3 shows the same-pressure piston seal according to the present invention in a state in which pressure is applied and the first speech-action side portion is twisted. 4 and 5 show conventional piston seals for same pressure. 1... Bis l Henshir for both sides. 2...18 moving side part. 3...Fixed side part. 8...Tanibe. 9... Thin wall part. 12...Protruding part. 14...Tapered surface. 17...The tip of the valley. 25...Curved surface 26...Second valley. 31... Cylinder tube surface. 32... Piston. 33... Seal mounting groove. 34... Vortex type surface. 35...Groove side patent applicant Narukami Seisakusho Co., Ltd. Representative Kiyoo Takaishi

Claims (1)

[Scope of Claims] 1) A sliding surface having a sliding surface consisting of a circular arc protrusion provided at the center of the outer sliding surface and both tapered surfaces that touch the arc and connect the outer peripheral ends of both side surfaces. A fixed side part consisting of a side part, an inner peripheral protrusion provided on both ends of the inner peripheral surface in contact with the groove bottom, and a recess in the center of the inner peripheral surface, by one small circular arc provided on both sides. A dual-pressure piston seal for a fluid pressure cylinder, characterized in that it has a vertically symmetrical cross-sectional shape connected by a thin wall section sandwiched by a trough consisting of a tip, a sliding side, and a fixed side slope. 2) The dual-pressure piston according to claim 1, wherein the protruding portion of the outer circumferential sliding surface is constituted by a plurality of small circular arcs and a recess provided between the circular arcs. sticker. 3) The sliding surface according to claim 1, wherein the sliding surface between the arc of the sliding surface and the outer circumferential end of both side surfaces is formed of a curved surface centered on the thin wall portion. Piston seal for pressure. 3) The dual-pressure piston seal according to claim 1, wherein the height of the sliding side portion is lower than the height of the fixed side portion. 4) Claim 1 characterized in that a second trough portion shallower than the trough portion separating the sliding side portion and the fixed side portion is provided on both inner peripheral side surfaces of the fixed side portion. Double pressure piston seal as described.